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  <div class="question_difficulty">
   难度：Easy
  </div>
  <div>
   <h1 class="question_title">
    183. Customers Who Never Order
   </h1>
   <p>
    Suppose that a website contains two tables, the
    <code>
     Customers
    </code>
    table and the
    <code>
     Orders
    </code>
    table. Write a SQL query to find all customers who never order anything.
   </p>
   <p>
    Table:
    <code>
     Customers
    </code>
    .
   </p>
   <pre>
+----+-------+
| Id | Name  |
+----+-------+
| 1  | Joe   |
| 2  | Henry |
| 3  | Sam   |
| 4  | Max   |
+----+-------+
</pre>
   <p>
    Table:
    <code>
     Orders
    </code>
    .
   </p>
   <pre>
+----+------------+
| Id | CustomerId |
+----+------------+
| 1  | 3          |
| 2  | 1          |
+----+------------+
</pre>
   <p>
    Using the above tables as example, return the following:
   </p>
   <pre>
+-----------+
| Customers |
+-----------+
| Henry     |
| Max       |
+-----------+
</pre>
  </div>
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   <h1 class="question_title">
    183. 从不订购的客户
   </h1>
   <p>
    某网站包含两个表，
    <code>
     Customers
    </code>
    表和
    <code>
     Orders
    </code>
    表。编写一个 SQL 查询，找出所有从不订购任何东西的客户。
   </p>
   <p>
    <code>
     Customers
    </code>
    表：
   </p>
   <pre>+----+-------+
| Id | Name  |
+----+-------+
| 1  | Joe   |
| 2  | Henry |
| 3  | Sam   |
| 4  | Max   |
+----+-------+
</pre>
   <p>
    <code>
     Orders
    </code>
    表：
   </p>
   <pre>+----+------------+
| Id | CustomerId |
+----+------------+
| 1  | 3          |
| 2  | 1          |
+----+------------+
</pre>
   <p>
    例如给定上述表格，你的查询应返回：
   </p>
   <pre>+-----------+
| Customers |
+-----------+
| Henry     |
| Max       |
+-----------+
</pre>
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